Kuwaiti algorithm: Difference between revisions

Revision as of 11:16, 26 January 2009

Revision as of 15:09, 26 January 2009

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[[Microsoft]] uses the '''Kuwaiti algorithm''' to convert between dates in the Western standard [[Gregorian calendar]] and dates in the Hijri or [[Islamic calendar]]. There is no fixed correspondence defined in advance between the Gregorian [[solar calendar]] and the Islamic [[lunar calendar]], since the latter is defined by the visibility of the new moon by religious authorities and can therefore vary by a day or two, depending on the particular Islamic authority, weather conditions, and other variables. As an attempt to make conversions between the calendars somewhat predictable, Microsoft claims to have created this [[algorithm]] based on statistical analysis of historical data from [[Kuwait]]. However, its results are identical to a variation of the [[tabular Islamic calendar]], which was introduced by Islamic astronomers around the eighth century. {{Fact|date=January 2009}}

Inevitably, any arithmetic algorithm is imprecise, and results often differ by a day or two from observation or complex calculation.

==Behavior of Kuwaiti algorithm==

''Note: This was determined by inspection of the output of the software and is possibly wrong for dates that were not examined.'' {{orOriginal research|date=January 2009}}

*Common (non-leap) years have 354 days. Leap years have 355 days.

*Odd-numbered months of the year have 30 days. Even-numbered months have 29 days. Exception: the 12th month of a leap year has 30 days.